it is possible , with a straight board of hickory, to mark out a template Ffirst draw your centre line with a string or straight edge, then mark out your front and side , precalculated profiles. Then cut this out, this will make a satisfactory bow if done correcectly and will work with amy board bow. A stave can be squared up and treated this way too.
True, following the grain will improve performance, but it is not essential.....An elb design may not bring out the best in a hickory stave though
dave